Read down the left-hand edge to the number showing solar amps or watts your wire will carry.
Follow that line across to the right to find your wire length in feet from solar to batteries. At the top of the column above your
wire length is the minimum wire size (gauge) to use. Smaller gauge equals larger
wire.
Buried DC cables must be copper, wet aluminum with DC corrodes quickly.
If your total solar power is over 25 amps, it is best to divide the solar into
two smaller groups
and run separate pairs of cables to
a 30 amp breaker for each group.
Copper Wire Size and Length Table, 5%
loss for 12 VOLT Wiring |
|
|
12ga |
10ga |
8ga |
6ga |
4ga |
2ga |
1/0 |
2/0 |
3/0 |
AMPS |
WATTS |
Distance in feet to run wire below,
Wire size above
|
4 |
48 |
43 |
68 |
113 |
178 |
288 |
450 |
725 |
900 |
- |
6 |
72 |
30 |
43 |
75 |
119 |
188 |
300 |
481 |
600 |
760 |
8 |
96 |
21 |
36 |
56 |
88 |
144 |
225 |
363 |
450 |
570 |
10 |
120 |
17 |
28 |
45 |
71 |
113 |
180 |
290 |
360 |
457 |
15 |
180 |
11 |
17 |
30 |
47 |
75 |
120 |
193 |
240 |
304 |
20 |
240 |
8 |
13 |
22 |
36 |
56 |
90 |
145 |
180 |
229 |
25 |
300 |
- |
11 |
17 |
28 |
45 |
72 |
115 |
145 |
183 |
30 |
360 |
- |
8 |
15 |
23 |
37 |
60 |
96 |
120 |
152 |
40 |
480 |
- |
- |
11 |
17 |
28 |
45 |
72 |
90 |
114 |
50 |
600 |
- |
- |
- |
13 |
22 |
36 |
57 |
72 |
91 |
Copper Wire Size and Length Table, 5% loss for 24
VOLT
Wiring |
|
|
12ga |
10ga |
8ga |
6ga |
4ga |
2ga |
1/0 |
2/0 |
3/0 |
AMPS |
WATTS |
Distance in feet to run wire
below, Wire size above |
4 |
96 |
87 |
137 |
226 |
356 |
576 |
900 |
- |
- |
- |
6 |
144 |
60 |
87 |
150 |
238 |
376 |
600 |
962 |
- |
- |
8 |
192 |
42 |
72 |
112 |
177 |
288 |
450 |
726 |
900 |
- |
10 |
240 |
35 |
57 |
90 |
142 |
226 |
360 |
580 |
720 |
914 |
15 |
360 |
22 |
35 |
60 |
95 |
150 |
240 |
386 |
480 |
608 |
20 |
480 |
17 |
27 |
45 |
72 |
112 |
180 |
290 |
360 |
458 |
25 |
600 |
- |
22 |
35 |
57 |
90 |
145 |
230 |
290 |
366 |
30 |
720 |
- |
17 |
30 |
47 |
75 |
120 |
192 |
240 |
304 |
40 |
960 |
- |
- |
23 |
35 |
57 |
90 |
145 |
180 |
228 |
50 |
1200 |
- |
- |
- |
27 |
45 |
72 |
115 |
145 |
182 |
Copper Wire Size and Length Table, 5% loss for 48
VOLT
Wiring |
|
|
12ga |
10ga |
8ga |
6ga |
4ga |
2ga |
1/0 |
2/0 |
3/0 |
AMPS |
WATTS |
Distance in feet
to run wire below, Wire size above |
4 |
192 |
174 |
274 |
452 |
712 |
1152 |
1800 |
- |
- |
- |
6 |
288 |
120 |
174 |
300 |
476 |
752 |
1200 |
1924 |
- |
- |
8 |
384 |
84 |
144 |
224 |
354 |
576 |
900 |
1452 |
1800 |
- |
10 |
480 |
70 |
114 |
180 |
284 |
452 |
720 |
1160 |
1440 |
1828 |
15 |
720 |
44 |
70 |
120 |
190 |
300 |
480 |
772 |
960 |
1216 |
20 |
960 |
34 |
54 |
90 |
144 |
224 |
360 |
580 |
720 |
916 |
25 |
1200 |
28 |
44 |
70 |
114 |
180 |
290 |
460 |
580 |
732 |
30 |
1440 |
24 |
34 |
60 |
94 |
150 |
240 |
384 |
480 |
608 |
40 |
1920 |
18 |
26 |
46 |
70 |
114 |
180 |
290 |
360 |
456 |
50 |
2400 |
- |
22 |
28 |
54 |
90 |
144 |
230 |
290 |
364 |
Source: Backwoods Solar Electric Systems
|